Patient selection: The clinical decision for a fluid challenge is often used as an eligibility criterion.
Conversely, sternotomy (open chest conditions) increases cardiac preload, decreases stroke volume variation and probably decreases the sensitivity of the heart to fluid challenge.
Timing of intervention: Ventricular function influences response to fluid challenge and is not constant in critically ill patients.
Timing of assessment Although not always specified, many studies evaluate response to fluid challenge immediately following or soon after the completion of the fluid infusion (16,46,62,67-73).
Moreover, additional research is warranted with regard to defining which patients need fluid challenge in terms of clinical benefit.
Measurements of right ventricular volumes during fluid challenge.
Respiratory variations in right atrial pressure predict the response to fluid challenge.